ABSTRACT Chagas disease, caused by Trypanosoma cruzi, represents the third greatest tropical disease burden. CD affects >7 million people, causes >17000 deaths, and costs ~$8.0 billion per year in health care costs and lost productivity. Infected individuals present oxidative and inflammatory stress, ventricular fibrosis and dilatation, and eventually develop congestive heart failure. In this project, we propose to examine a novel role of poly (ADP-ribose) polymerase 1 (PARP1) in chagasic pathology and offer an innovative potential therapy. Briefly, we believe that PARP1 cross-talk with mitochondrial DNA polymerase G (POLG) effects the mtDNA integrity, leading to a decline in respiratory chain efficiency and increase in mitochondrial reactive oxygen species (ROS) production in cardiomyocytes and chagasic heart. Moreover, phagocytosis of ROS-induced cell debris along with PARP1-dependent metabolic switch in macrophages signals activation and proliferation of proinflammatory macrophages. We will employ innovative, fluorescence-based, assays that measure multiple functional responses in the same sample to test our hypothesis in two specific aims. In aim 1, our objectives are to demonstrate that PARP1 activation increases the risk of clinical heart disease in infected patients, dissect how PARP1 interferes with mtDNA replisome with increasing severity of heart disease, and test that targeted delivery of PARP1 inhibitors to mitochondria preserves mitochondrial health and LV function in Chagas disease. In aim 2, our objectives are to test that extracellular vesicles (EV) produced due to ROS/PARP1-induced cellular injury carry the immune signature of chronic Chagas disease. We will demonstrate that EVs, in a disease stage-specific manner, engage intracellular innate immune receptors of macrophages, and macrophage expression of PARP1 provides metabolic signal for glycolytic switch and proinflammatory m? activation. Importantly, we will test that controlling PARP1 activation is beneficial in silencing the tissue- destructive, inflammatory phenotype of chagasic patients? macrophages. We believe the innovation lies in the idea of demonstrating how a DNA repair protein can disturb mitochondrial function and intensify inflammation. We will provide mechanistic insights into how these processes are linked and offer a novel therapy for preserving metabolic homeostasis and LV function in Chagas disease cases.